So I'm fishing for ideas on how to assign the C1, C2, and C3 modes on the 5D Mk II. I'll be upgrading from a Rebel XT, where I primarily use Tv and Av functions (sometimes full manual) anyway. I very rarely use the other automatic modes.

Given the things you can customize in those modes, what will most people be using those settings for? A mode for mostly night shooting? Flash shooting? ISO settings? I think ISO is the other thing I change most often on my current camera.

Any kind of suggestion for ideas of what to set these to (with specific settings if possible!) would be appreciated.